The present invention relates generally to agricultural implements such as grain drills or the like, and more specifically to structure for raising a selected portion of a plurality of ground engaging tools on such an implement while leaving the remaining tools in the normal ground working position.
The driving pattern farmers use to seed fields with implements such as grain drills varies widely. Some follow the outside perimeter with consecutive paths moving toward the center of the field and then over seeding of the diagonals of the field. Others seed straight paths followed by seeding of the headlands, a method which results in the problem of double seeding, especially when a field is irregularly shaped. Of course, the larger the drill, the larger the area that will be double seeded. Growing popularity of large drills has magnified the double seeding problems of seed costs and poor crop performance due to overpopulation of seeds.
Attempts to overcome the double seeding problems have included electronic control of drive clutch engagement to selectively disengage drive to meters which feed the openers that would otherwise be double seeding. One problem with selective drive clutch disengagement is that the openers remain in contact with the ground and disturb areas that have already been planted. Such contact increases opener wear and upsets the critical seed/soil environment which, in turn, can reduce yields.
In systems with down pressure regulation such as available on the John Deere 455 Series Folding Grain Drill and shown and described in U.S. Pat. No. 5,065,681, cylinders for controlling vertical tool movement and down pressure on the sections are connected in parallel. Heretofore there has been no convenient and inexpensive way to raise tools on one or more of the sections to avoid double seeding and disturbance of previously seeded areas.